Categories
Software Development

Running PHPUnit Tests with WordPress Plugins (easily)

phpunit testing

If you are developing plugins for WordPress, one of the pain points I’ve struggled with is getting tests running. In the future, I need to document getting javascript tests running. Today, I’m going to outline the method for running phpunit tests. I will also discuss several problems I encountered along the way.

First: use @wordpress/env

This tool deserves a post all on it’s own but long story short, it allows a quick method to bootstrap a local development environment using docker. After installation it’s available as wp-env or npx wp-env (and I’ll be using the shorter version in this post).

The most basic “working” version of this is a .wp-env.json file in your plugin directory that looks like:

{
	"plugins": [ "." ]
}Code language: JSON / JSON with Comments (json)

Launch the environment with wp-env start. (WordPress is downloaded and stored locally. Next it creates docker-compose file mapping several containers: wordpress, cli, mysql, tests-wordpress, tests-cli, and tests-mysql.

Second: use wp-cli to create the scaffolded plugin-tests

> wp-env run tests-cli wp scaffold plugin-tests $(basename $(pwd))
Success: Created test files.
✔ Ran `wp scaffold plugin-tests sample-plugin` in 'tests-cli'. (in 24s 436ms)Code language: Shell Session (shell)

The above command creates a bunch of files that aren’t technically necessary and you can remove them (e.g. .circleci, bin/install-wp-tests.sh, .phpcs.xml.dist).

By passing the --ci parameter you can change the continuous integration provider. With wp-env you’ll need to add -- --ci=github.

Third: get it running

In theory you should be able to run wp-env run tests-cli phpunit, but that runs in the wrong directory. Solution: pass the current working directory.

> wp-env run tests-cli --env-cwd=wp-content/plugins/sample-plugin phpunit
ℹ Starting 'phpunit' on the tests-cli container.

Error: The PHPUnit Polyfills library is a requirement for running the WP test suite.
If you are trying to run plugin/theme integration tests, make sure the PHPUnit Polyfills library (https://github.com/Yoast/PHPUnit-Polyfills) is available and either load the autoload file of this library in your own test bootstrap before calling the WP Core test bootstrap file; or set the absolute path to the PHPUnit Polyfills library in a "WP_TESTS_PHPUNIT_POLYFILLS_PATH" constant to allow the WP Core bootstrap to load the Polyfills.

If you are trying to run the WP Core tests, make sure to set the "WP_RUN_CORE_TESTS" constant to 1 and run `composer update -W` before running the tests.
Once the dependencies are installed, you can run the tests using the Composer-installed version of PHPUnit or using a PHPUnit phar file, but the dependencies do need to be installed whichever way the tests are run.
✖ Command failed with exit code 1
Command failed with exit code 1Code language: Shell Session (shell)

Whoops, it looks like some libraries are missing. Let’s add them.

composer require --dev yoast/phpunit-polyfillsCode language: JavaScript (javascript)

That installs the library, but also gives us a version of phpunit we need to use to ensure they are loaded. With that slight change we see:

> wp-env run tests-cli --env-cwd=wp-content/plugins/sample-plugin vendor/bin/phpunit
ℹ Starting 'vendor/bin/phpunit' on the tests-cli container.

Installing...
Running as single site... To run multisite, use -c tests/phpunit/multisite.xml
[03-Oct-2024 18:17:14 UTC] PHP Warning:  Class "PHPUnit\Framework\Error\Deprecated" not found in /wordpress-phpunit/includes/phpunit6/compat.php on line 8
[03-Oct-2024 18:17:14 UTC] PHP Warning:  Class "PHPUnit\Framework\Error\Notice" not found in /wordpress-phpunit/includes/phpunit6/compat.php on line 9
[03-Oct-2024 18:17:14 UTC] PHP Warning:  Class "PHPUnit\Framework\Error\Warning" not found in /wordpress-phpunit/includes/phpunit6/compat.php on line 10
[03-Oct-2024 18:17:14 UTC] PHP Warning:  Class "PHPUnit\Framework\Warning" not found in /wordpress-phpunit/includes/phpunit6/compat.php on line 12
[03-Oct-2024 18:17:14 UTC] PHP Warning:  Class "PHPUnit\Framework\TestListener" not found in /wordpress-phpunit/includes/phpunit6/compat.php on line 15
Not running ajax tests. To execute these, use --group ajax.
Not running ms-files tests. To execute these, use --group ms-files.
Not running external-http tests. To execute these, use --group external-http.
PHPUnit 11.3.6 by Sebastian Bergmann and contributors.

Runtime:       PHP 8.2.24
Configuration: /var/www/html/wp-content/plugins/sample-plugin/phpunit.xml.dist

No tests executed!
✔ Ran `vendor/bin/phpunit` in 'tests-cli'. (in 1s 34ms)Code language: Shell Session (shell)

Why weren’t any tests run?

Because WordPress doesn’t like the latest version of phpunit. Let’s change it with composer require -W --dev phpunit/phpunit ^9.6

> wp-env run tests-cli --env-cwd=wp-content/plugins/sample-plugin vendor/bin/phpunit
ℹ Starting 'vendor/bin/phpunit' on the tests-cli container.

Installing...
Running as single site... To run multisite, use -c tests/phpunit/multisite.xml
Not running ajax tests. To execute these, use --group ajax.
Not running ms-files tests. To execute these, use --group ms-files.
Not running external-http tests. To execute these, use --group external-http.
PHPUnit 9.6.21 by Sebastian Bergmann and contributors.

No tests executed!
✔ Ran `vendor/bin/phpunit` in 'tests-cli'. (in 1s 32ms)Code language: Shell Session (shell)

Still no tests… 🤔

Oh! the phpunit.xml.dist is excluding the only test. Remove that line:

--- phpunit.xml.dist	2024-10-03 11:28:06.212985211 -0700
+++ 2phpunit.xml.dist	2024-10-03 11:28:39.641072205 -0700
@@ -1,16 +1,15 @@
 <?xml version="1.0"?>
 <phpunit
 	bootstrap="tests/bootstrap.php"
 	backupGlobals="false"
 	colors="true"
 	convertErrorsToExceptions="true"
 	convertNoticesToExceptions="true"
 	convertWarningsToExceptions="true"
 	>
 	<testsuites>
 		<testsuite name="testing">
 			<directory prefix="test-" suffix=".php">./tests/</directory>
-			<exclude>./tests/test-sample.php</exclude>
 		</testsuite>
 	</testsuites>
 </phpunit>Code language: Diff (diff)

And success! 🎉

> wp-env run tests-cli --env-cwd=wp-content/plugins/sample-plugin vendor/bin/phpunit
ℹ Starting 'vendor/bin/phpunit' on the tests-cli container.

Installing...
Running as single site... To run multisite, use -c tests/phpunit/multisite.xml
Not running ajax tests. To execute these, use --group ajax.
Not running ms-files tests. To execute these, use --group ms-files.
Not running external-http tests. To execute these, use --group external-http.
PHPUnit 9.6.21 by Sebastian Bergmann and contributors.

Test 'SampleTest::test_sample' started
Test 'SampleTest::test_sample' ended


Time: 00:00.021, Memory: 38.50 MB

OK (1 test, 1 assertion)
✔ Ran `vendor/bin/phpunit` in 'tests-cli'. (in 0s 927ms)Code language: Shell Session (shell)

Other investigations/changes

  • phpunit 10 changes the way it finds tests. In the future, the file name and the class will need to agree (e.g. rename file to SampleTest.php and change phpunit.xml.dist to find files like *Test.php).
  • WordPress needs to update its support of phpunit too.
  • If you are using a javascript build process:
    • Add @wordpress/env as a development requirement.
    • Add a script to your package.json to run tests: "test": "wp-env run tests-cli --env-cwd=wp-content/plugins/sample-plugin vendor/bin/phpunit"
    • Now you can just run npm test!
  • Need more investigation about using wp-env in continuous integration environment.

Fin

As of October 3, 2024, these steps worked on getting an up-to-date sample plugin running phpunit tests using wp-env.